Japan scientists detect rare, deep-Earth tremor

Scientists who study earthquakes in Japan said Thursday they have detected a rare deep-Earth tremor for the first time and traced its location to a distant and powerful storm. The findings, published in the US journal Science, could help experts learn more about the Earth's inner structure and improve detection of earthquakes and oceanic storms. Using seismic equipment on land and on the seafloor that usually detects the Earth's crust crumbling during earthquakes, researchers found something they had not detected before -- a tremor known as an S wave microseism.